Skyrme-Random-Phase-Approximation description of spin-flip and orbital giant resonances

TL;DR

This paper extends the self-consistent SRPA model with Skyrme forces to magnetic excitations, analyzing spin-flip and orbital giant resonances in Nd isotopes, revealing deformation effects and a three-peak structure in the response.

Contribution

It introduces an extension of the SRPA model to magnetic excitations and applies it to Nd isotopes, providing insights into resonance structures and deformation effects.

Findings

Onset of scissors mode with increasing deformation

Identification of a three-peak structure in spin-flip response

Qualitative agreement with experimental data, but quantitative discrepancies remain

Abstract

The self-consistent separable random-phase approximation (SRPA) model with Skyrme forces is extended to the case of magnetic excitations and applied to the description of spin-flip and orbital M1 giant resonances in the isotopic chain $^{142-152}$Nd. The Skyrme forces SkT6, SkM*, SLy6 and SkI3 are used. The calculations show the onset of the scissors mode with increasing deformation. A specific three-peak structure of the spin-flip response is found and explained by particular neutron and proton spin-flip transitions. Although the employed forces provide an acceptable qualitative description, the Skyrme functional still needs further improvement to reproduce quantitatively the experimental data.